They are fairly similar across science festivals, though they come under a variety of names: Expo Day, Science Carnival, Science Street Fair, and Discovery Days to name a few.

For our purposes let's just call them the "Main Event." These are the big number days, when tens of thousands of people swarm a wide array of interactive booths set up by many different exhibitors, often with stage performances and wonderful spectacles.

But as big as the Main Events might be, it is crucial that we don't lose the bigger picture: there can be so much more to a science festival.

I was riding the T this weekend in Boston, and had that quintessential mass transit experience. Even though the car was packed it was silent, with everyone minding their own business. The train inexplicably screeched to a halt in the middle of the tunnel (the Green line always screeches).

As our wait turned into minutes, a boy started asking mom questions. When he asked what building we were under now, a stranger got into the guessing game. Several in the car started eavesdropping on this small diversion, and then joining in to suggest landmarks on the streets above, each more obscure than the next.

It always seems special and rare to have a great exchange with complete strangers.

Large-scale science festivals can be resource intensive. They often require a significant fund-raising effort (they seem to end up costing roughly $10 per person served, roughly the same as most science centers). But they also depend on the energies of a whole community of  partners and collaborators. Are they worth the money and time?

Evaluations conducted by the Science Festival Alliance have already shown some of the unique benefits of the festival format. Strengths include reaching new audiences, and involving researchers directly in public outreach. We will soon make these and additional findings public. However, two recent initiatives are taking festival impacts beyond the once-a-year celebration, and extending the benefits--and value--of science festivals to the rest of the calendar year.

1. Festival as match-maker between attendees and year-round programs

Is it too early for science story of the year nominations? This one seems to have it all: rats tripping on acid, the seedy world of underground chemists in Europe, and a spiraling number of murder victims.

...well, maybe they are murder victims. It's hard to say.

This is the story of David Nichols, who studies the way psychedelics act in the brains of rats. One side effect of Dr. Nichols's published findings is that black market labs decipher the recipes for "cheap and marginally legal recreational drugs." Some of these recipes have been involved in deaths.